// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_WM_PUBLIC_ACTIVATION_CLIENT_H_
#define UI_WM_PUBLIC_ACTIVATION_CLIENT_H_

#include "ui/aura/aura_export.h"

namespace ui {
class Event;
}

namespace aura {
class Window;

namespace client {
    class ActivationChangeObserver;

    // An interface implemented by an object that manages window activation.
    class AURA_EXPORT ActivationClient {
    public:
        // Adds/Removes ActivationChangeObservers.
        virtual void AddObserver(ActivationChangeObserver* observer) = 0;
        virtual void RemoveObserver(ActivationChangeObserver* observer) = 0;

        // Activates |window|. If |window| is NULL, nothing happens.
        virtual void ActivateWindow(Window* window) = 0;

        // Deactivates |window|. What (if anything) is activated next is up to the
        // client. If |window| is NULL, nothing happens.
        virtual void DeactivateWindow(Window* window) = 0;

        // Retrieves the active window, or NULL if there is none.
        virtual Window* GetActiveWindow() = 0;

        // Retrieves the activatable window for |window|, or NULL if there is none.
        // Note that this is often but not always the toplevel window (see
        // GetToplevelWindow() below), as the toplevel window may not be activatable
        // (for example it may be blocked by a modal transient, or some other
        // condition).
        virtual Window* GetActivatableWindow(Window* window) = 0;

        // Retrieves the toplevel window for |window|, or NULL if there is none.
        virtual Window* GetToplevelWindow(Window* window) = 0;

        // Returns true if |window| can be activated, false otherwise. If |window| has
        // a modal child it can not be activated.
        virtual bool CanActivateWindow(Window* window) const = 0;

    protected:
        virtual ~ActivationClient() { }
    };

    // Sets/Gets the activation client on the root Window.
    AURA_EXPORT void SetActivationClient(Window* root_window,
        ActivationClient* client);
    AURA_EXPORT ActivationClient* GetActivationClient(Window* root_window);

    // Some types of transient window are only visible when active.
    // The transient parents of these windows may have visual appearance properties
    // that differ from transient parents that can be deactivated.
    // The presence of this property implies these traits.
    // TODO(beng): currently the UI framework (views) implements the actual
    //             close-on-deactivate component of this feature but it should be
    //             possible to implement in the aura client.
    AURA_EXPORT void SetHideOnDeactivate(Window* window, bool hide_on_deactivate);
    AURA_EXPORT bool GetHideOnDeactivate(Window* window);

} // namespace clients
} // namespace aura

#endif // UI_WM_PUBLIC_ACTIVATION_CLIENT_H_
